SSD Components and Make Up – An SSD Primer

In our first article entitled ‘Benefits of The Solid State Drive‘ we briefly provided comparison between a SSD and a hard drive and described the benefits of such an upgrade.

We are going to follow with a description of SSD components along with an understanding of the purpose of each. This article will not only provide a solid foundation in your understanding of SSDs, but also, will also help in your final decision and choice of the right SSD for the job. If it helps in your purchase decision, it has to be good right?

Every SSD has a number of components that are always present. There are different SSD form factors which we will cover in our next article but, for the most part, there is always a printed circuit board (PCB) which contains a interface to connect to the computer, SSD controller and a number of modules of NAND flash memory chips.

We have chosen to highlight the OWC Mercury Electra 6G SSD for this article because it is a 2.5″ typical notebook formfactor and the most common that most likely see today.

SATA INTERFACE

The SATA interface is best seen in the left photo above and consists of a gold connector which easily connects to your laptop or desktop computer. Without belaboring on the definition and revisions of SATA, the consumer only really needs to understand that all SATA SSDs are backward and forward compatible and any will serve the purpose it is intended without question. Most computer systems in use are SATA 2 with newer systems now released with SATA 3 capability.

The difference between the two breaks down to how fast the data can be transferred from the SSD to your computer and, in the case of applications, executed. Typically, a SATA 2 SSD will only transfer speeds as fast as 280 megabytes per second (MB/s) whereas new SATA 3 drives are reaching as high as 550MB/s in a single form factor notebook or desktop SATA 3 SSD. Lets take a look at two typical benchmarks, the one on the left depicting the Sandisk Ultra SATA 2 SSD performance with the one on the right depicting the Corsair Force Series GT SATA 3 SSD.

We can see that these are not peak results, this being the fault of the benchmark software for the most part. An important observation, however, is that SATA 3 typically doubles the performance of SATA 2.

SSD PROCESSOR OR CONTROLLER

The SSD processor (or controller is it is more commonly referred to) is the heart and soul of the SSD. It is the engine by which information is pulled from storage, translated and then sent to the SATA interface for travel to your computer system. It is the sole reason that a typical SSD is 5-6 times faster than a hard drive in data travel and also the reason that we see a starting point of about a 90x increase in the information retrieval (disk access) from an SSD as compared to that of a hard drive.

Our first article explained how access speed is attained so quickly through the continuous flow of data in a SSD much like a pipeline in comparison to the mechanical movement, location and retrieval of data from a hard drive. Unlike a hard drive which has only one route of information retrieval, the typical SSD can have as many as eight routes of travel or ‘channels’ as they are more commonly referred to. So, if you can again refer back to the OWC SSD above you will note that their are 16 NAND flash memory chips that are used for storage. This would mean that every two has its own channel ‘or highway’ by which to send and receive information.

PROCESSOR TYPES

In today’s SSD environment there are two common processors which differ in their means of storage. The first utilizes compression to store data, debatably the most popular and a company named SandForce (recently purchased by LSI) is the only that has perfected it. In observing performance benchmarks, a SandForce SSD can be easily identified as it is able to achieve almost equal read and write transfer speeds where others cannot do this. This is only possible because SandForce has been able to achieve a 1 to .6 write ratio which allows for almost equal read and write performance.

I guess it’s safe to assume you’ll be covering in more detail how the die sizes, process shrinks and empty/unused controller channels make for slower and slower small drives and eventually may end up requiring you to buy a 512gb drive of some models (cough-Octane-cough) just to get the max performance. I even came across an article that predicts that SSDs will ultimately commit slow suicide with the continuing die shinks and resulting lower and lower write speeds.

I’ve answered TONS of posts on Ocz’s forums from users who don’t understand why their 60GB V3 is so slow vs a 120 or 240…and TWICE as many who don’t understand the write penalty with incompressible data on a SF controller and proceed to post an as_ssd or CDM screeny asking where the specd 500reads/500writes are.

Guest again

Oh speaking of process shrinks…if anyone is in the market for a 34nm toggle equipped SF2200 (i.e. Ocz MaxIOPs) you better get ’em while you can…transition to 24nm toggle is upon us. Similar to the 32nm to 25nm transition, write speeds will take a hit as well as the base durability (P/E cycles) even tho it will bring the price down further…but I’m the type who doesn’t mind paying a little extra for the faster writing drive with more durable nand.

MRFS

p.s. My message above suddenly disappeared (??)

MRFS

MRFS

Thanks, Les.

I think your entire website would benefit enormously by expanding your working definition of “solid-state”.

Clearly, the IT world has more or less adopted “SSD” as the preferred acronym for memory devices that utilize one of several variants of Nand Flash e.g. MLC and SLC in different die sizes, different controllers and varying capacities with or without internal DRAM cache.

However, a ramdisk that utilizes SDRAM to emulate a file system partition would also qualify as a “solid-state” memory technology.

This latter approach to accelerating the speed of most recently used “working sets” has taken on added important with the release of chipsets that support 6 and now 8 DIMM slots e.g. Intel’s X79 chipset with quad-channel memory access.

See our “Technical Review and Evaluation of RamDisk Plus Software”.

KEEP UP THE GOOD WORK!

MRFS

Rteprecision32

Hopefully the issues with SSD failures, BSOD, lost data, compatibility and reliability issues will be discussed for those who are unaware that consumer grade SSDs are “immature tech” and a potential liability for anyone who needs secure data.

Guest

Sounds like your referring pretty much to SF’s teething pains…hardly representative of the entire SSD industry. SSDs are no worse than HDD failure rates btw…

sgogeta4

Typo on the beginning of page 2, you wrote Samsung will release a 520 with SF controller, but I know you meant Intel.

Mike

Thanks Les now I need to find the buyers at the factories. I have a whole bunch of Flash that I want to sell. mhayward@t-online.demhayward@t-online.de

David L.

I just got a SSD, it came with it’s own transfer software. For some reason it did not work very well. so I went to my old standby ACRONIS. I treated the SSD as the same way I would any other drive. I used Widow’s partition manger to set it up, works fine. Also I purchased a UPS power supply to protect the SSD from power frailer, there cheep and will protect your equipment.